Carbon paper ink containing a trimellitic acid-alkanol-neopentyl glycol polyester



United States Patent O CAREGN PAPER ENK CCNTAINENG A THEIR 3E3 LiTiC AClD-ALKAlJQL-NEGEENTYL GLYCQL PGLYESTER Ronald L. Broadhead, Park Forest, IlL, assignor to Standand 653 Company, Chicago, 13., a corporation of lntliana No Drawing. Filed Mar. 31, 1060, Ser. No. 18,806

Claims. (Cl. 260-23) This invention relates to carbon paper and ink suitable for the preparation of carbon paper.

At the present time, carbon papers are prepared with ink (also called dope) containing as the important ingredient carnauba wax. Carnauba wax is of such importance in carbonizing inks because it imparts exceptionally' good flow qualities to the finished ink and also has exceptional oil retention at ordinary temperatures for the oil contained in the ink. Other vegetable waxes, particularly ouricury, are utilized in the carbon paper ink but almost always in conjunction with carnauba wax. Carnauba Wax is an expensive material and being of natural origin frequently varies in quality, dependent upon natures weather and the care taken by the suppliers in the selection and purification of the wax. Heretofore, no one has been able to develop a replacement for carnauba wax; at best, wax-like materials have been provided which are capable of extending the carnauba wax in the formulation.

It has been discovered that a hereinafter defined resin possesses waxy characteristics of a nature which permit the formulation of carbonizing inks without using in the formulation any carnauba wax or any other Wax such as is normally used in carbon paper ink. The waxy resin is utilized along with mineral oils of the usual type used in carbonizing ink and a color-afifording ingredient to obtain a coating composition suitable for the preparation of carbon paper. In addition to these three essenital ingredients, carbon paper ink can be prepared which includes hydrocarbon wax and/or vegetable waxes. (Carnauba wax may be included in the coating com position of the invention but without imparting any favorable qualities beyond those already present in a composition not containing carnauba wax.)

For convenience, the coating composition i.e., carbonizing ink; carbon paper ink ingredients are described in detail in separate sections hereinafter.

WAXY RESIN The waxy resin ingredient of the coating composition isthe resin polyesterification-condensation reaction product of a monoester of a t-rimellitic acid or anhydride and a primary alkanol containing from-at least 18 to about 36 carbon atoms with an alkanediol to obtain a resin having an Acid. Number (mg. KOH per g. of resin) of not more than about 30.

Instead of using an already existing monester,. a

be: and an alkanol, the acidic memberzalkanol reaction charge is in a mole ratio of about 1:0.91.1 and preferably eqnimolar.

The acidic member and the alkanol are vigorously agitated and the reaction carried out at a temperature below about 120 C.this is in order to avoid formation of diesters and triesters. Generally the monoester reaction is carried out at a temperature from about C. to 120 C., and more usually from about C. C.

The Waxy resin is obtained by condensing the monoesters and an alkanediol containing from 2 to 6 carbon atoms in a straight chain between hydroxyl groups and a total of not more than 12 carbon atoms, such as ethylene glycol, propylene glycol, and 1,6-hexandiol. Particularly suitable a-lkanediols are neopentyl glycol and 1,4-butanediol.

The condensation reaction is carried out under more or less conventional conditions for polyesteritication- The reaction zone is vigorously condensation reactions. agitated to'improve contacting while the temperature is maintained between about C. and 225 C., commonly on the order of C. Water produced in the reaction is continuously withdrawn. The time of reaction is determined by the type of reactants and the temperature of reaction; the waxy solid resin product has an Acid Number of not more than about 30.

When an essentially pure monester is used in the condensation reaction, the mole ratio of said al-kanediol to said monoester in said reaction zone is about 0.9-1.2:1 and preferably 1.1-1.2:1.

In the more usual instances when the monoester is made by direct reaction of acidic member and alkauol before the condensation reaction, the ratio of reactants in the condensation zone is related to the acidic member charged to the monoester prepared for simplicity in directions. The mole ratio of acidic member in the charge to the monoester preparation to the alkanediol is about 1:0.91.1 and is preferably 1:1.

The resin obtained from the condensation reaction is a waxy solid with, usually, a glossy surface. These waxy resins are very soluble in hydrocarbons which are solvents for natural Waxes and solid paratlins. Examples of these solvents are" naphtha, benzene, mineral spirits, toluene and chlorobenzenes. .These resins also have a large solubility in alcohols, such asisop-ropanol and monoester may be made as a first step in the preparation a of the resin by the ester reaction of the acid or anhydride with an alkanolor mixture thereof-containing from at least 18 to about 36 carbon atoms. Illustrative primary alkanols are stearyl, C18; docosanol, C ceryl, C myricyl, C and hexatriacontyl, C and the mixture of C C and C alkanols available commercially, where the C alkanol is the predominant component; a particularly suitable mixture of these alkanols contains 90% or more of the C alkanol.

The acidic reactant is a trimellitic acid or tritnellitic anhyd'ride.

When the monoesteris formed from the acidic membutanol.

Resins suitable for use in the ink of the invention are illustrated below:

' V Waxy Resin N0. 1

In an ordinary beaker provided with a propeller stirrer, equipmolar amounts of trimellitic auhydride and a commercial mixture (Aldol 60) of C C and C alkanols'- 90% of the -C were reacted at a temperature over the range of 100 15 5 C. At the beginning thebeaker contained a slurry ofsolid .anhydride particles in the liquid alcohols; at the solid of monoester. I

-98 g. (0.2 mole) of this'monoester and 26 g. (0.25 mole) of neopentyl glycol were reacted, with vigorous stirring, in a flask fitted with a reflux condenser and watertrap, at -195 C. for 4 hours. The produce was a pale tan, waxy resinwith an Acid Number of 30.

30 grams. of the resin was dissolved in 90 grams of mineral spirits by warming. The mineral spirits Was apetroleum hydrocarbon having an ASTM distillation range of 307 F.-397 F. (153 C.230 .C.), a flash point of 104 F. (40 C.) and a Kauri-Butan-ol- No. of

end,- the beaker contained a pasty ered as; hydrocarbon waxes.

;: 51A? bro d particular f irmu'lation-consists ofjabout 25;-

. Waxy Resin No. 2

Another waxy resin was prepared by reacting equimolar amounts of trimellitic anhydride and of the commercial Aldol 6O alkanol mixture described in Waxy Resin N0. l; and 1.2 moles of 1,4-butanediol per mole of the rnonoester. 'The reaction procedure was substantially identical with that described for Waxy Resin No; 1. The.

solid product Waxy Resin No. 2 was a pale tan solid having an Acid Number of about 25.

Waxy Resin No.3 V A third resin was prepared by preparing a monoester from the reaction of 1 mole of trimellitic anhydride With a mixture of 0.5 mole of Aldol 6 and 0.5 mole of octa decanol. The 'monoester-was *then condensed with 1.2 moles of neopentyl glycol under the conditions described for Waxy Resin No. 1. Number of 28.

. OIL

' "The carbonizing ink composition of the invention ineludes an oil of the type commonl'y'utiliz ed in carbonizing inks known at this time. -Broadly, the composition includes a mineral oil having an SSU viscosit -y at 100 1 of about 70425SSU meansSeconds Saybolt Universal.

These mineral oils may include the very highly refined Theproduct resin .had an Acid dient ranges from about 1 to about 25 Weight percent; and

V the remainder is essentially only mineral oil. The color afiording ingredient will be present in an amount which is determined by the particular ingredient and the particular use. Forexample, when carbon black is utilized it is present generally in an amountfrom about 4-18 Weight percent. Organic dye stuifs generally are present in an it is to be understood that exist informulations dependent upon the end use of the amount from about '13 'weightpercent. In addition to the mineral oil, minor amounts of other oils such as red oil, castor oil, and'peanut oil may be present.

A broad particular formulationincluding hydrocarbon waxes'consists of about 1 25 Weight percent of :color' affording ingredient; about zero25 weight percent of hydrocarbon waxes,-about 5 015 weightper'cent of Waxy resin -and-the remainder essentially only the hereinbefo're efined mineral oil; The hydrocarbon wax and the waxy resin are presentgin a relationsuch that the sum of the resin and the wax' present 'isat least about 40 weight per:

g 3 cent, butenot more, than about SOweight, percent; When thewax. content is zero then Itheresin content is at least about'25. weight percent. Y

' particular carbonizing ink formulation. "It isnot. intended products sold as technical White. oils or medicinal white 2 oils. Or they may include oils of the lubricating oil type which have been solvent extracted or acid treatedto improve storage stability and color. These oils may be of a pour point suitable for the particular final use of the car, bon paper. The particular mineral oil will be selected in 2 terms of -the ultimate use of the finished carbon paper COLOR The color, affording ingredient utilized in: the coating composition of the invention may be any-"bf those 'pigmerits or dye stuifs utilized in presently available carbon papers. The most important pigment is carbon black; normally utilized in combination with a dye tonerwhen a particular blackcol'or is :desired. Another important I 7 OTHER waxes i M The coating composition .ofptheinvention may include otherwaxes of the types normally utilized in carbon paper preparation. i These waxes may include, the vegetable V waxes such as carnauba, ouricury, andcandelillajinse'ct waxes suchas beeswax an'd'shellac; animal wax suchas spermacetij petroleum waxes suchas paraflin-wax, petrol j latum wax, and high meltingmicrocrystallinewaxes; min eral waxes such as 'montans' and ozokerite. Hereinafter.

the petroleum waxes and the mineral waxes are considsetout; I.

OATING coMrosrrrorr Y tinting composition of the'inv'entionconsists 63m *tiallyj ot-imineral oilhaviiig an SSU viscosity atlQO F.

of -about* f7( )'42 5, the color 'afiording ingredient' 'a'ndthe hereinabove defined waxy resin.

weight percent of waxy iresin; the color affording ingre thatthebroad particular formulations'described above limitthe scope ofthe coating composition of the'invention because thoseof ordinary "skill in; this'art may readily devise .ajlarge number as illustrated by the multiplicity V of carbon inktormulations available-of' formulations suitable for a particular purpose in the preparation of carbon papers. a

I CA BON PAPER T I Thecoating composition ofithe invention is applied to a a suitable base paper v (carbonizing tissue) to obtain the finishedcarbon paper i' The carbonizing tissues may be any of those utilized inthepreparation of presently avail- 1 able commercial carbon papers. Chapter XII of Specialty Papers,Their Properties and Applications, 1950, Remsen Press, sets forth the large number of difrerent carbonizing tissues available to'and utilized by carbon paper manufacturers; It is' to be understoodthat the carbon' paper ofthe invention may utilizeany of these base papers (car- :ingink of the invention; V e j The methods of preparation of carbon papers now utilized and described in chapter XII of the above cited reference may be utilized with the coating composition of the 2 A p en'cilco'pying" #4 6 Qabot carbonfblack v p v I The heated charge "was ground together} pestle and thenhotlcoated on onion skin copying'propertieswere obtained. 1

bonizing tissues)"for accepting a coating of the carbonizinvention to prepare carbon pap ers ofthje invention.

' EXAMPLES 1 *A'number offca'rbonizing ink formulations were made, 'up and used in'the preparationeof carbon paper. suitable. fortype'writerorrpencilcopying; In allqof. these formulation's', cornme'rciallyavailable' carbon black, dye stuffs, 1 paraifin wax, 1 carnauba 'wax,j and 'mineral oil were used. I i The mineraloilutilized "was'a solvent extracted lu'bricat-' T e. aniount'of these other waxes presentjinfl e Coatin 1 has? gs-tiqck tme n SS 'V1SC9s1ty at- 1 of g composition. may vary from :zero to whatever :amount is. i suitable for the particular formulation required; The par-e tioulantype of other wax used will; be dependent upon the ultimate-useio'f thecarbon paperprepared frornitheformu- 1 lation. 7 l1 7 V f v, s, Ithas been discovered thatia very good-carbonizingink' includes-the waxy-resin, hydrocarbon wax, coloraifording ingredient, and rnineral oil in a relationship hereinafterv 89:. The waxy; resins utilized 1 in th'e" formulationswere thosedescribed in the section on Waxy-Resins. 'The carbon papers Were prepared byapplying inkv at a tempera iwr QfilWiZW E; 1 s

considerable variation may hi pr odiict was particularlyisuitable for The charge was ball milled together for 30 minutes at 90-1l0 C. The resulting cake was firm and coated readily on onion skin paper. The charge was very fluid at 80 C. The carbon paper prepared from this ink gave good typewriter copying properties. The copies were quitesm'udge resistant but could be erased in case of error in typing.

' Example 111 2.0 grams additional waxy resin were added to 18.50 grams of the ink of Example II and blended in at 80 C. to give a veryfluid mix at this temperature. The product showed good typewriter copying properties, clearness, sharpness, and smear resistance.

Example IV I A violet pencil copying ink:

Grams Waxy Resin N0. 2 10.0 122-125 F. melting parafnn 20.0 SX mineral oil 10.0 Crystal Violet 1.0

The charge was melted together and stirred for 2 minutes to give a firm cake at room temperature. The product hot coated on onion skin paper to give a paper with very sharp, clear pencil copying characteristics.

Example V A violet pencil copying ink using higher melting paraffin:

(It will be observed that here no oleic acid was used to disperse the dye.) The charge was ball milled together at 80-86 C. for minutes. The resulting ink was very fluid at this temperature, and the ball mill yield was 87.6%. This latter value is a measure of the fluidity of the product. This product showed no change in viscosity upon heating for S'Weeks at 190-200 F.

Example VII A black typewriter and pencil copying ink:

v Grams Waxy Resin No. 3 84.0- 122-125 F. melting paraflin 24.0 SX5 mineral oil a 97.0 Crystal Violet 4.0 Carbon black 26.0

Ball milled together for minutes at 98-100 C. The resulting paper required somewhat more aging one week as opposed to 3 days for the other carbon containing formulations to attain maximum hardness. Copying properties were good. Ball mill yield 92%.

6 Example VIII A violet ink containing some carnauba wax:

Grams Waxy Resin No. 2 5.0 Carnauba wax 5.0 122-125 F. melting parafiin 10.0 SX5 mineral oil 20.0 Crystal Violet 0.40

The ink gave sharp copying properties when converted to carbon paper but there was no evident improvement as a result of the inclusion of the vegetable wax.

Example IX The inks of Examples l-Vlll were stored in stoppered containers in a oven held at a temperature of 190-200 F. for 21 days. None of these inks showed any change in viscosity or the appearance of thixotropy after this storage test. (This test is of importance in that storage under these conditions of commercial formulations which do not contain significant amounts of carnauba wax or ouricury wax usually show a large viscosity increase or the development of a thixotropic body.)

Example X A blend was prepared of 10 grams of Waxy Resin No. 1, 10 grams of microcrystalline wax (170-175 F. melting point), and 20 grams of medicinal white mineral oil having a viscosity of 300 seconds Saybolt Universal at 100 F. This blend was fluid and showed good flow quality at 160 F. The blend was cooled to room temperature of about 75 F. A solid cake was formed. This cake did not bleed oil or even show oil droplets on the surface. The cake could be snapped readily by finger pressure. The solid cake produced by this blend showed all of the desirable room temperature characteristics possessed by good quality carnauba wax-oil blends at these conditions.

Thus having described the invention, what is claimed is:

' taining from 2 to 6 carbon atoms in a straight chain between hydroxyl groups and a total of not more than 12 carbon atoms in a mole ratio of said alkanediol to said monoester of from about 0.911 to about 1.2:1, said reaction being at a'temperature between about 125 C; and 225 C., with continuous withdrawal'of Water of reaction to obtain a Waxy solid resin product having an Acid Number of not more than about30. g

2. The composition of claim 1 wherein said resin is prepared by the polyesterification-condensation reactionof (A) the monoester made'by reacting (i) an acidic member selected from the class consisting of trimellitic acid and anhydride thereof and (ii) a primary alkanol containing from at least 18 to about 36 carbon atoms, in a mole ratio of said acidic memberto said alkanol of about 1:0.9l.1 at a temperature below about C., and '(B) an alkanediol containing from 2 to 6 carbon atoms in a straight chain between hydroxyl groupsand a total of not more than 12 carbon atoms, in a mole-ratio of acidic member present in the charge to Ato said alkanediol of from about 1:0.91.2.

3. The composition of claim 2 wherein said acidic member is trimellitic anhydride. i

f}. The composition of claim 2 wherein said alkanol is a mixture of primary alkanols having 18-22 carbon atoms, and the C alkanol is the predominant alkanol'.

5. The composition of claim 2 wherein saidalkanediol is neopentyl glycol.

6. An ink adapted for the preparation of color afiording ingredient; (B)-'about 25-50 weight perpared by the polyesterification-condensation reaction of carbon paper? which ink consists of (A) about 1-25 weight percent of amaasa Saybolt Universal at 100 FL, and saidresin is prepared 'by the polyesterification-condensation reaction of (I) a (l) a monoester of an acidic member selected from the class consisting of trimellitic acid and anhydride thereof and a primary alkanol containing from at least 18 toabout 36 carbonatoins and (II) analkanediol containing from 2 to 6 carbon atoms in a straight chain between hydroxyl groups and a total of not more than 12 carbonatoms, ina

mole ratiovof said alkanediol to said monoester of from' about 0.9:1 to about 1.221, said reaction being at a tem v perature between about 125 C. and 2-25 (2Q, withcontinuous withdrawal of water of reactionto obtain a waxy solid resin product having 'an'i'A cid Number of not more thanv'about 30: p 7 V p t 7. Carbon paper consisting of carbonizing tissue coated with the'ink of claim 6.

50-15 weight percent of'waxy resin, thesum of the wax a mineral oil having a viscosity of about 70425 seconds i monoester oftan acidic member selected from the class consistingtof trimellitic' acid' and anhydride thereof and a primary alkanol containing from at least 18 to about 36 carbon'atoins and (II) an alkanedioI containing from 2 to 6 carbonatoms in a straight chain between hydroxyl 7 groups and a totaliof not more than 12 carbon atoms, in

amole ra'tioof said alkanec liolto said monoes'ter'of from fabout0.9:l to about 1.2: 1, said reaction "being at a temperatu're between about 125 C.'and 225 C., with continuous withdrawal of water of reaction, to obtain a waxy solid resin'product having anfAcid Number'ofinottmore than about 30. a V t it 1, t

9. Carbon paper consisting of carbonizing tissue" coated with the ink of claim 8. I

10'. The composition' of claim 2 'wherein said acidic 7 member is'trimellitic anhydride, said alkanol is a mixture oflprimary alkanols having 18-22'ca1-bon atoms, and the 20 V V I t diol is neopentyl-g lycol. p v 8. A carbo'nizing inkconsistingof'tA) about 1-25 i 1 weight percent of color aifording iugredient, B) about zeroweightpercent of hydrocarbon wax, (C) about a V '25 and resin p e n being fromat least about 40 to about weight percent and the resinv being'at least about 25 when wax is zero, and (D) theremainder essentially only- (3 alkanol is the predominanqalkanol, and said alkane- I; nrerscssjcna i; the sle t this pass f UNITEDVSTATESIPATENTS j a 2,421,291; Schniutzle 2,426,248 Sugarman 7 Aug. 26, 1947 T 2,'890,125 Mange e "June 9,1959

Bolton et a1.

n June 7, 1960 

1. A COATING COMPOSITION SUITABLE FOR PREPARATION OF CARBON PAPER WHICH COMPOSITION CONSISTS ESSENTIALLY OF (A) MINERAL OIL HAVING AN SSU VISCOSITY AT 100*F. OF ABOUT 70-425; (B) A COLOR AFFORDING INGREDIENT; AND (C) WAXY RESIN PREPARED BY THE POLYESTERIFICATION-CONDENSATION REACTION OF (1) A MONOESTER OF AN ACIDIC MEMBER SELECTED FROM THE CLASS CONSISTING OF TRIMELITIC ACID AND ANHYDRIDE THEREOF AND A PRIMARY ALKANOL CONTAINING FROM AT LEAST 18 TO ABOUT 36 CARBON ATOMS AND (II) AN ALKANEDIOL CONTAINING FROM 2 TO 6 CARBON ATOMS IN A STRAIGHT CHAIN BETWEEN HYDROXYL GROUPS AND A TOTAL OF NOT MORE THAN 12 CARBON ATOMS IN A MOLE RATIO OF SAID ALKANEDIOL TO SAID MONOESTER OF FROM ABOUT 0.9:1 TO ABOUT 1.2:1, SAID REACTION BEING AT A TEMPERATURE BETWEEN ABOUT 125*C. AND 225*C., WITH CONTINUOUS WITHDRAWAL OF WATER OF REACTION TO OBTAIN A WAXY SOLID RESIN PRODUCT HAVING AN ACID NUMBER OF NOT MORE THAN ABOUT
 30. 